Turbine wheel assembly



J. R. M VEIGH TURBINE WHEEL ASSEMBLY Aug. 13, 1957 2 Sheets-Sheet 1Filed May 15. 1952 INVEN TOR. JOHN R. McVEIGH BY DES JARDINS, ROBINSON8- KEISER HIS ATT ORNEYS Aug. 13, 1957 J. R. M VEIGH TURBINE WHEELASSEMBLY H 2 t mv. Tm w m n VR t N w w m J 2 5 9 l 5 l w M d e 1 i F DESJARDlNS,2BIN$ON & KElSER Wm,

H! S ATTORN EY$ 2,802,680 Patented Aug. 13, 1.957

TURBINE WHEEL ASSEMBLY John R.'McVeigh, Latrobe, Pa., assignor toKennametal Inc., Latrobe, Pa., a corporation of Pennsylvania ApplicationMay 15, 1952, Serial No. 287,847

11 Claims. (Cl. 287-53) The invention is an improvement over the turbinewheel assembly of my Patent 2,662,725 issued 'December; 15, 1953 fromearlier application Serial No. 145,635,.

filed February 23, 1950, and likewise has to-do with turbine wheels orimpellers that arereadily detachably assembly, opposite the shaftseating invention.

Fig. 2 is-a longitudinal sectional-view on line 2--2 of side, embodyingthe i Fig. 1.

mounted on the end of the shaft and adapted-to work at J temperaturesconsiderably higher than those to which the shaft is heated.

'ZThC' turbine impeller'or wheels are made of cemented hard; carbidecomposition, such as cemented titanium carbide, which present specialproblems because of their hardness. The turbine wheel or impeller has tobe 'mounted on the end of a steel shaft to transmit torque thereto, andordinary fastening means are not satisfactory since the cemented hardcarbide material is too hard to be milled or tapped by usual machineoperations.

There is also the problem of different coefficients of expansion of thesteel shaft and the cemented hard carbide wheel or impeller.

The present invention involves the same general principles as my earlierinvention in respect to securing and providing a centering means whichis unaffected by ,the coefficients of expansion of the parts of theassembly.

Accordingly, one of the principal objects of my invention is an assemblyof a turbine wheel and shaft, of

difierent coeflicients of expansion, which provides alarge area ofcontact for good lateral support between the elements.

Another object of the invention is provision of a turbine wheel havingits thickest portion at the center or hub, with the machined portions ofthe wheel for seating the shaft externally exposed.

Another object of the invention is to provide means on the wheel, ofsmall dimension, for cooperating with the centering means between saidwheel and shaft.

Still another object of the invention is to provide an assembly in whichthe parts are positively locked together. Other objects, and objectsrelating to details of construction, will definitely appear from'thedetailed description to follow. In one instance, I accomplish theobjects of my invention by the construction described in the followingspecification. The invention is clearly de- 'Fig. 3 is an-enlargedlongitudinal sectional view of the assembly at right angles to that inFig. 2.

Fig. 4 is an exploded view of the parts comprising the assembly.

Generally described, the invention comprises a turbine wheel orimpeller'having a thickened central portion with a hub projectionextending therefrom to which the shaft is connected, said projectionhaving two oppositely disposed flanges spaced from the central portionof the impeller and circumferentially spaced from each other. This hubprojection is also provided with a smaller centrally located post forcentering the shaft. A supporting annulus with a hub-engaging portion isinterposed between the central portion of the wheel and the shaft, thisbeing fitted into place when the shaft with assembly parts connectedthereto are connected to the wheel.

The impeller end of the shaft terminates in an integrally formed spider,or one attached thereto, the impeller end of the spider being providedwith a seat'for one end of a pilot sleeve that is interposed betweensaid spider and the wheel with its opposite end seated on the centeringpost of the wheel hub projection. An impeller .retaining'ring isfastened to the spider by an annular .series of clamp screws, said ringbeing provided with oppositely positioned, inwardly extending offsetears for engaging the overhanging flanges of the hub projection, theseears being engaged with the overhanging flanges by first fitting saidring axially upon the hub projection with the ears in alignment with thespaces between the flanges of the hub projection, and then turning thering A lock ring is located in the center of the retaining ring and isprovided with wings for filling the spaces between the flanges of thehub projection, said lock ring having a radial pin or pins forinterengaging with the retaining ring to prevent them turning relativelyto each other. The above-mentioned annularly disposed screws are thentightened to secure the parts in assembled relation. The supportingannulus, surrounding the retaining ring is interposed with one endseated against the spider and its opposite end against the centralportion of the impeller wheel to give increased lateral support.

Referring specifically to the drawings in which like numerals designatelike parts, numeral 2 indicates a hollow steel shaft having a spider 3integrally formed on one end thereof. The end face of the spider isprovided with an internal annular seat or cup 4 and an outer annularseat 5 for purposes hereinafter set forth, there being an intermediateweb 5 for seating the hereinafter described impeller retaining ring thatis clamped thereto.

A turbine wheel or impeller 6, preferably formed from cemented hardcarbide, is constructed to be detachably mounted on the end of thespider, said wheel having a central thicker portion 7 with radiallyextending blades 8. One side face of the central portion 7 of the Wheelis provided with a central hub projection 9 having, oppositely disposedflanges 10, spaced from the central portion of thewheel at 11, the innerfaces of the flanges being beveled at 12, and the flanges being spacedcircumferentially from each other, forming segmental spaces to receivethe wings 13 of lock ring 14 which is fitted to the hub projection 9with an impeller retaining ring 15 and locks the retaining ring againstturning. The retaining ring 15 is provided with two inwardly extendingears 16, offset laterally, for engaging the flanges 10 of the hubprojection 9. The retaining ring 15 is slipped on the hub projectionaxially with the inwardly extending ears in alignment with the spacesbetween flanges mental spaces between the ears 16 and the flanges 10.

The wall of the central recess 17 of the retaining ring '15 is providedwith circumferentially arranged cooling passages or holes 18, some ofwhich extend through the inwardly extending ears. Radial pins 19 areprovided on the lock ring 1d, at diametrically opposite points, toengage notches 18 in the retaining ring, to prevent said lock ring frombeing turned relative to the retaining ring when they are assembled.After the retaining ring is assembled in locking position with the hubprojection, it is bolted to the shaft spider 3 by screws 2t).

The hub projection 9 is also provided with a centering post 21, and apilot sleeve 22 is interposed between the shaft and the impeller wheel,the end of the sleeve 22 being seated in the internal annular seat orcup 4 of the spider with its opposite end seated on the centering post21 of the hub projection 9 by means of central opening 23 in the sleeve.An annular row of passages 24 is provided in the pilot sleeve 22 topermit the circulation of air through the shaft and the assemblyadjacent the face of the wheel.

In order to obtain a wider area of contact between the spider and thewheel and thereby provide greater lateral support, a supporting annulus25 is interposed therebetween, the edge 26 of the annulus fitting inseat 5 of the shaft spider and edge 27 fitted against the centralportion of the wheel near its outer periphery. Passages 28 are formed inthe annulus 25 to allow for the circulation of air therethrough. Thewall 32 of the central opening 33 in the supporting annulus 25 isprovided with an inturned bead 3t! in position to contact the outerportion of a heat insulating disc or bafiie 31 to be inserted betweensaid head and the edges of the wings 13 of the lock ring 14.

To assemble the impeller wheel 7 and shaft 2, the supporting annulus 25is first placed with its edge portion 27 resting on the central portionof the impeller wheel and the baffle 31 is then inserted to rest on thebead 30 with the hub projection 9 protruding through the central openingof the baffle. The impeller retaining ring 15 is then placed over thehub projection 9 and rotated through 90, so that ears 16 engage behindflanges it? to lock the retaining ring to the impeller. The lock ring14- is then inserted in the retaining ring 15 with pins 19 lodged innotches 18', thus preventing relative turning of rings 14 and 15. Thepilot sleeve 22 is then positioned on protruding centering post 21 andthe shaft 2 and spider 3 are positioned with the pilot sleeve 22received in the cup 4 of the spider, and seat 5 of the spider engagingthe edge portion 26 of the supporting annulus 25. The spider is thenfirmly secured to the impeller retaining ring 15 by screws 29, thussecuring all parts of the mounting to the impeller wheel and the shaft.

To carry heat away from the impeller, cooling air enters through holes28 in the supporting annulus 25, passes through holes 18 in theretaining ring 15, through holes 24 in the pilot sleeve and out throughtubular shaft 2.

From the foregoing description, it will be seen that the hub projection9 for making the assembly with the shaft spider is externally locatedand exposed so that it can be more readily machined. The centering post21 is of relatively small diameter, thus minimizing efiects due todifferences in coefiicients of expansion of the different materialsemployed. This provides a rigid mount, even though the temperatures andcoefiicients of expansion of the parts are different. Good heatinsulation and cooling between the impeller and the mount are provided.The impeller wheel is thickest at its hub portion where subjected to thegreatest stresses, and the face of the central portion of the wheelprovides for a large area of contact for the shaft spider so thatmaximum lateral support is obtained.

I am aware that there may be various changes in details of constructionWithout departing from the spirit of my invention, and, therefore, Iclaim my invention broadly as indicated by the appended claims.

Having thus described my invention, what I claim as new and useful anddesire to secure by U. S. Letters Patent is:

1. A turbine wheel and shaft assembly comprising the combination of awheel having a central hub projecting laterally from one side of thecentral portion of the wheel, said hub having a pair of diametricallyopposed radially extending flanges, circumferentially spaced from eachother and spaced from the said side of the central portion of the wheelto form a pair of notches, a centering post extending laterally from thehub coaxial therewith, a shaft terminating in a spider, a retaining ringdetachably secured to the spider and surrounding said hub, said ringhaving means for interlocking with said hub by rotation of the ringabout its axis, a locking means for preventing rotation of saidretaining ring about said hub, and a pilot sleeve seated on thecentering post and in the spider.

2. The turbine wheel and shaft assembly of claim 1 in which theretaining ring is provided with a pair of diametrically opposed inwardlyextending ears engageable in the notches between said flanges and thecentral portion of the wheel.

3. The turbine wheel and shaft assembly of claim 2 in which the lockingmeans is pinned to the retaining ring to prevent them from turningrelative to each other.

4. The turbine wheel and shaft assembly of claim 3 in which the lockingmeans is in the form of a lock ring provided with laterally extendingwings received in the spaces between the'ears of the retaining ring andthe flanges of the hub.

5. The turbine wheel and shaft assembly of claim 1 including asupporting annulus surrounding the retaining ring and seated against thespider and the central portion of the Wheel.

' 6. The turbine wheel and shaft assembly of claim 5 in which aninsulating disc is interposed between the supporting annulus and thehub.

7. A turbine Wheel and shaft assembly comprising the combination of awheel having a hub projecting laterally from the center of one sidethereof, a retaining ring surrounding said hub, said hub and ring havinglocking flanges adapted to interengage upon rotation of the ring on thehub to prevent movement of the ring axially of the hub, means to preventturning of the ring relative to the hub, a shaft having a spider fixedto one end thereof, and means for detachably securing the spider to theretaining ring.

8. The turbine wheel and shaft assembly of claim 7 including asupporting annulus surrounding the hub and ring and seated on the sideof the wheel and on the spider.

9. The turbine wheel and shaft assembly of claim 8 including a centeringpost projecting axially from the end of the hub and a pilot sleeveseated on said post and within said spider.

10. The turbine wheel and shaft assembly of claim 9 in which the shaftis tubular and the annulus, ring and pilot sleeve are provided withports for the passage of air therethrough, whereby cooling air may enterthrough said annulus, circulate through the ring and sleeve, and passout through the tubular shaft.

11. The turbine wheel and shaft assembly of claim 10 including a heatinsulating disc supported by the annulus, surrounding the hub, andinterposed between the side of the wheel and the retaining ring.

(References on following page) 5 6 References Cited in the file of thispatent 2,557,747 Judson et a1 June 19, 1951 UNITED S A A S 2,602,683A116 y 8, 1952 1,403,201 Shaw Jan. 10, 1922 FOREIGN PATENTS 1,838,935FiXsen D60- 9, 193 5 903,268 France Jan. 10, 1945 2,051,965 Roth Aug.25, 1936

